Driverless cars could only make traffic 33% better

According to writer Brian Christian and cognitive scientist Tom Griffiths, co-authors of "Algorithms to Live By: The Computer Science of Human Decisions," the difference in congestion between total chaos and a perfectly-ordered driving system — the kind proposed in a future with autonomous vehicles — is only about 33%.

"If you're hoping that networked, self-driving autonomous cars will bring us a future of traffic utopia," they write, "it may be disheartening to learn that today's selfish, uncoordinated drivers are already pretty close to optimal."

Aside from the fact you'll get to sleep on your way into the office, driverless cars earn a lot of praise for how efficient they'll make the experience of driving. Cars will be able to talk to one another when they change lanes or need to slow down, the thinking goes, so there will be no uncertainty from drivers to create traffic.

Computer science is less optimistic.

The finding that chaos is only slightly worse than perfection actually comes from a 2002 academic paper written by computer scientist Tim Roughgarden. He discovered that when routers shuffle packets of data across the Internet without an organized system — known formally as "selfish routing" — the price of anarchy is only a 33% reduction in speed versus top-down order.

Christian and Griffiths argue the principle can be applied to any number of systems where huge batches of data are whizzing past one another, highway traffic included.

Self-driving cars can avoid accidents, which are a major cause of slowdown on some roads. And they can drive more tightly together, which can also increase the throughput of roads, Christian tells Tech Insider. "But the broader point here is that traffic is primarily a function of congestion — that there are more cars on the road than the road is built to handle."

In other words, it doesn't matter that much if all six lanes of California's 101 are filled with driverless cars. They're still filled with driverless cars. Efficiency assumes the existence of wiggle room.

Chris Dixon, a partner at the prestigious Silicon Valley investment firm Andreessen Horowitz, recently told Tech Insider that driverless cars will still afford society a host of benefits. Ride-sharing will eliminate cars taking up needless space in parking lots, and the move from gas to electric will help the environment.

But according to Christian and Griffiths, unless there is more top-down order from urban planners — new roads, smarter routing — to divert people away from crowding major highways, the benefits to traffic will be minimal.

"Congestion will always be a problem solvable more by planners and by overall demand," they write, "than by the decisions of individual drivers, human or computer, selfish or cooperative."